package com.sjy.security;

import java.io.IOException;


import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.access.AccessDeniedException;
import org.springframework.security.access.SecurityMetadataSource;
import org.springframework.security.access.intercept.AbstractSecurityInterceptor;
import org.springframework.security.access.intercept.InterceptorStatusToken;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.annotation.web.servlet.configuration.EnableWebMvcSecurity;
import org.springframework.security.web.FilterInvocation;
import org.springframework.security.web.access.intercept.FilterInvocationSecurityMetadataSource;
import org.springframework.stereotype.Service;



@Service
@EnableWebSecurity
public class MyFilterSecurityInterceptor extends AbstractSecurityInterceptor implements Filter{
	
	 //标记自定义的url拦截器已经加载
    private static final String FILTER_APPLIED = "__spring_security_filterSecurityInterceptor_filterApplied_dynamically";

    private boolean observeOncePerRequest = true;

	@Autowired
    private FilterInvocationSecurityMetadataSource securityMetadataSource;

    @Autowired
    public void setMyAccessDecisionManager(MyAccessDecisionManager myAccessDecisionManager) {
        super.setAccessDecisionManager(myAccessDecisionManager);
    }
    public void setSecurityMetadataSource(FilterInvocationSecurityMetadataSource newSource) {
        this.securityMetadataSource = newSource;
    }

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {


    	FilterInvocation fi = new FilterInvocation(request, response, chain);
        invoke(fi);
    }


    public void invoke(FilterInvocation fi) throws IOException, ServletException {
    	//fi里面有一个被拦截的url
    	//里面调用MyInvocationSecurityMetadataSource的getAttributes(Object object)这个方法获取fi对应的所有权限
    	//再调用MyAccessDecisionManager的decide方法来校验用户的权限是否足够
        InterceptorStatusToken token = super.beforeInvocation(fi);
        
        try {
        	//执行下一个拦截器
            fi.getChain().doFilter(fi.getRequest(), fi.getResponse());
        } finally {
            super.afterInvocation(token, null);
        }
    	 
          }
    


    @Override
    public void destroy() {

    }

    @Override
    public Class<?> getSecureObjectClass() {
        return FilterInvocation.class;

    }

    @Override
    public SecurityMetadataSource obtainSecurityMetadataSource() {
        return this.securityMetadataSource;
    }
}
